The present invention relates to an apparatus for inserting tuft assemblies in a mattress.
As is known, in order to prevent excessive bulging due to the pressure of the internal springs against the filling layers, mattresses are kept flat by a plurality of retention elements, known as tuft assemblies, one of which is shown for the sake of clarity in FIG. 1 of the accompanying drawings.
In said FIG. 1, the tuft assembly is designated by the reference letter P and comprises a tension element T, which consists of a tape that has two bars S1 and S2 at its opposite ends. Tuft assemblies of this kind are known for example from British patents no. 903,464 and 1,541,077.
The tuft assemblies are inserted through the mattress by way of suitable manually actuated needles such as those disclosed for example in the cited British patents or by way of automatic apparatuses such as those disclosed in U.S. Pat. No. 6,032,345 and U.S. Ser. No. 10/126,535 by the same Applicant.
In these devices, the needle performs a forward stroke by means of which it draws the tension element and one bar through the mattress. When, at the end of the forward stroke, the bar exits from the opposite side of the mattress with respect to the one where the needle entered, it is released by the needle so that the two bars rest on the opposite faces of the mattress.
To prevent the mattress for tearing or being damaged by the friction thereon of the bars during use, protective elements are interposed between such bars and the surface of the mattress and are constituted by substantially circular disks made of felt or other suitable material, often known by the English term xe2x80x9ctuftxe2x80x9d.
In the apparatuses according to U.S. Pat. No. 6,032,345, EPA-1,167,279 and U.S. Ser. No. 10/126,535, the disks are distributed by devices that are designed so as to align the individual disks with the needle when the needle crosses the mattress. However, these devices have some substantial flaws. First of all, they have a limited capacity and must be reloaded frequently with disks. Secondly, they cannot ensure the alignment of the disks with the needle during the insertion of the tuft assemblies through the mattress. The needle, in passing through the mattress, in fact is often subjected to deviations from the penetration line that make it engage the disks off-center.
The aim of the present invention is therefore to provide an apparatus that does not suffer the drawbacks noted above.
Within this aim, an object of the present invention is to provide an apparatus that has a high production capacity and is reliable in operation.
This aim and this and other objects are achieved with an apparatus for inserting, through a mattress, tuft assemblies constituted by a flexible tension element that has, at its opposite ends, two bars that are arranged in a T-shaped configuration or other similar retention elements and are adapted to abut, with the interposition of a first disk and of a second disk or of another similar protective element, against the opposite faces of the mattress, said apparatus comprising a structure for locking said mattress that is composed of: two walls, which are flat and mutually parallel and delimit a space for accommodating a mattress that is compressed to a thickness that is shallower than the length of the tuft assemblies; a first carriage, which is supported by one of said walls and supports a first disk feeder and a device for inserting tuft assemblies through said mattress; a second carriage, which is supported by the second one of said walls and supports a second disk feeder; means for actuating said carriages along a preset path; said insertion device comprising: a tuft assembly loader; a needle that is guided at right angles to said mattress and has a tip that is provided with a seat that is suitable to receive a first bar of a tuft assembly that is fed by said loader; and means for actuating said needle through said mattress between a position in which said tip is upstream of the mattress, in order to receive said first bar in said seat, and a position in which said tip is downstream of the mattress, in order to release said bar from said seat; first means, mounted on said first carriage, for picking up a disk from said first feeder and placing it upstream of said mattress and in alignment with said needle; and second means, mounted on said second carriage, for picking up a disk from said second feeder and placing it downstream of said mattress and in alignment with said needle; characterized in that each one of said disk feeders comprises a disk magazine that is supported on a respective carriage and is suitable to contain disks arranged so as to form a stack that is perpendicular to said mattress and pusher means that act on said stack in order to keep the front disk of said stack in a pick-up position, and in that each one of said pick-up and placement means comprises a transfer element, which is supported by said carriage and is actuated so as to pick up said front disk from said magazine and transfer it in alignment with said needle.